Advanced Analysis Of Plane Steel Frames

The current analysis and design of steel frames consists of applying the first-order elastic analysis with various amplification factors and the interaction equations. Determination of the K factors and individual member capacity checks which are rather tedious and time exhausting are necessary. The advanced analysis combines the stability theory with the plastic theory, can capture the strength and stability of a whole structure and its individual members in the model of analysis so that K factors and individual member capacity checks are not required. The advanced analysis of plane steel frames is conducted in this thesis. Especially, the following aspects will be included:(1) The advanced analysis method, refined plastic hinge analysis, which is practical, is discussed. Stability functions are derived to account for P -δeffect. Element stiffness matrix is derived to account for the P -Δeffect. The transformation matrices and the modification of element stiffness for the formation of plastic hinges are discussed. The CRC tangent modulus concept is used to account for gradual yielding due to residual stresses. The parabolic model is assumed to simulate the degradation of element stiffness due to the plastification of the steel. And the initial geometric imperfection models are discussed.(2) The design progress of steel frames using the AISC-LRFD method is conducted. Included the magnification factor B1 accounts for the secondary P -δmember effect in all frames and the P -Δstory effect in unbraced frames; the K factor that has been employed to approximately estimate the influence of the overall structural system on the strength of beam-column members; the interaction equations of beam-columns; the beam curves and the column curves implicitly account for residual stresses and initial geometric imperfection. Then the Vogel frame is analysised using this method.(3) The Frame Advanced Analysis Program (FAAP) based on the refined plastic hinge analysis method is programmed using MATLAB. And the Vogel's frame is analysised using FAAP. Comparison to the plastic-zone method, which is the exact solution, the FAAP program is accurate enough.